/* 
 * Copyright (c) 2016, NVIDIA CORPORATION. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *  * Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *  * Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *  * Neither the name of NVIDIA CORPORATION nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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 */

#pragma once

#include <optixu/optixu_matrix_namespace.h>
#include "sutilapi.h"

namespace sutil 
{
 
class Arcball
{
  //
  // Note: all 2d units are in normalized [0,1] screen coords
  //
public:

  SUTILAPI Arcball( const optix::float2& center, float radius )
    : m_center(center), m_radius(radius)
  {}
  
  SUTILAPI Arcball() 
    : m_center( optix::make_float2( 0.5f ) ), m_radius(0.45f)
  {}

  // Return incremental rotation.  Does not save state.
  SUTILAPI optix::Matrix4x4 rotate(const optix::float2& from, const optix::float2& to) const;

private:

  optix::float3 toSphere(const optix::float2& v) const;

  const optix::float2 m_center;
  const float         m_radius;
};

} // namespace sutil

